1. Field of the Invention
The present invention relates to an integrated electronic component and, in particular, to an integrated electronic component in which a metal case is mounted on a ceramic substrate incorporating circuit elements and/or having circuit elements mounted thereon.
2. Description of the Related Art
An integrated electronic component disclosed in Japanese Unexamined Patent Application Publication No. 2002-353071 is known as an integrated electronic component incorporating circuit elements, such as capacitors and inductors, and/or having such circuit elements mounted thereon. With reference to FIG. 5, such an integrated electronic component has a metal case 5 disposed on top of a substrate 1 which is composed of a plurality of laminated ceramic sheets.
The substrate 1 incorporates circuit elements (not shown) in its interior and also has circuit elements 4 on its top surface, external electrodes 2 on its front and back surfaces, and external electrodes 3 on its side surfaces. The metal case 5 having a substantially box-like shape is mounted on top of the substrate 1. Terminals 6 protruding from the front and back surfaces of the metal case 5 are soldered to the external electrodes 2 to be electrically connected thereto.
In these integrated electronic components, the metal case 5 frequently receives external downward force A. For example, during assembly of the metal case to the substrate 1, measurement of the electrical characteristics of a finished product, or mounting of the finished product on a wiring board, a tool used in this process pushes down the top surface of the metal case 5. Thus, bottom edges of the metal case 5 push against the top surface of the substrate 1 due to the external force A, thereby disadvantageously causing chips or cracks on the corners 1a of the top surface of the substrate 1.
Stress caused by the force A tends to concentrate on the corners 1a of the top surface of the substrate. In addition, the corners 1a are the weakest portions of the substrate 1, thus being easily damaged.